center_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Possible explanation for high incidence of Chagas in some Peruvian communities (2015, June 18) retrieved 18 August 2019 from https://phys.org/news/2015-06-explanation-high-incidence-chagas-peruvian.html More information: Bottlenecks in domestic animal populations can facilitate the emergence of Trypanosoma cruzi, the aetiological agent of Chagas disease, Proceedings of the Royal Society B, DOI: 10.1098/rspb.2014.2807AbstractFaeces-mediated transmission of Trypanosoma cruzi (the aetiological agent of Chagas disease) by triatomine insects is extremely inefficient. Still, the parasite emerges frequently, and has infected millions of people and domestic animals. We synthesize here the results of field and laboratory studies of T. cruzi transmission conducted in and around Arequipa, Peru. We document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more than 85%). By inoculating guinea pigs, an important reservoir of T. cruzi in Peru, and feeding triatomine bugs on them weekly, we demonstrate that, while most animals quickly control parasitaemia, a subset of animals remains highly infectious to vectors for many months. However, we argue that the presence of these persistently infectious hosts is insufficient to explain the observed prevalence of T. cruzi in vector colonies. We posit that seasonal rains, leading to a fluctuation in the price of guinea pig food (alfalfa), leading to annual guinea pig roasts, leading to a concentration of vectors on a small subpopulation of animals maintained for reproduction, can propel T. cruzi through vector colonies and create a considerable force of infection for a pathogen whose transmission might otherwise fizzle out. © 2015 Phys.orglast_img